1. Field of the Invention
This invention relates to a semiconductor device and its manufacturing method, specifically to a CSP (Chip Size Package) type semiconductor device using a supporter and its manufacturing method.
2. Description of the Related Art
A CSP has received attention in recent years as a new packaging technology. The CSP denotes a small package having about the same outside dimensions as those of a semiconductor die packaged in it. A BGA (Ball Grid Array) type semiconductor device has been known as a kind of CSP. A plurality of ball-shaped terminals made of metallic material such as solder is arrayed on one of surfaces of the BGA type semiconductor device.
In order to increase packaging density, reducing a thickness of the semiconductor die is required, which in turn requires reducing a thickness of a semiconductor substrate as well. When the thickness of the semiconductor substrate is reduced, however, carrying the semiconductor substrate becomes impossible since reduced strength of the substrate causes warping and fracturing of the substrate during the manufacturing process. Therefore, it has been practiced that a supporter such as a glass substrate or a protection tape is bonded to one of surfaces of the semiconductor substrate and the semiconductor substrate is reduced in thickness by grinding the other surface of the semiconductor substrate to which the supporter is not bonded.
FIG. 29 is a cross-sectional view showing an outline of a conventional BGA type semiconductor device with the supporter. A semiconductor integrated circuit 101 made of elements such as CCD (Charge Coupled Device) type image sensors and CMOS type image sensors is formed in a surface of a semiconductor substrate 100 made of silicon (Si) or the like. Pad electrodes 102 that are electrically connected with the semiconductor integrated circuit 101 are formed on an insulation film 103 that is formed on the surface of the semiconductor substrate 100. The pad electrodes 102 are covered with a passivation film 104 made of a silicon nitride film or the like.
A supporter 105 made of a glass substrate or the like is bonded to the surface of the semiconductor substrate 100 through an adhesive layer 106 made of epoxy resin or the like. The supporter 105 is thick enough to firmly support the semiconductor substrate 100 that is to be reduced in thickness during the manufacturing process and to prevent the supporter 105 from being warped or fractured. For example, when the thickness of the semiconductor substrate 100 is to be reduced to about 100 μm, a thickness of the supporter is about 400 μm.
An insulation film 107 made of a silicon oxide film, a silicon nitride film or the like is formed on a side surface and a back surface of the semiconductor substrate 100. Wiring layers 108 each electrically connected with corresponding each of the pad electrodes 102 are formed on the insulation film 107 along the side surface and the back surface of the semiconductor substrate 100. A protection layer 109 made of solder resist or the like is formed to cover the insulation film 107 and the wiring layers 108. Openings are formed in the protection film 109 at predetermined regions on the wiring layers 108. There are formed ball-shaped conductive terminals 110, each connected with corresponding each of the wiring layers 108 through corresponding each of the openings, respectively.
The semiconductor device described above is manufactured through a process including a process step (so-called dicing process) in which the supporter 105, the protection film 109 and the like are cut with a dicing blade along predetermined dicing lines DL that make borders between individual semiconductor devices.
The technology mentioned above is disclosed in Japanese Patent Application Publication No. 2006-93367, for example.
Although the semiconductor device described above has the protection film 109 that covers the wiring layers 108 connected with the pad electrodes 102, poor moisture resistance of the protection film 109 and the adhesive layer 106 made of hygroscopic material at a contacting portion with the supporter 105 or the like causes a problem of reliability that the supporter 105 comes unstuck from the semiconductor substrate 100.
The number of dicing lines DL has increased as micro-fabrication has advanced to increase the number of dice per wafer. The conventional manufacturing method in which the dicing is carried out along each of the dicing lines DL at a time causes another problem that the dicing process takes a lot of time. In particular, when a highly rigid material such as a glass substrate is used as the supporter 105, difficulty to cut the supporter 105 makes additional reason to extend time required in the dicing process. In addition, electronic equipment has been required incorporating more functions while reducing its thickness.
This invention is directed to offering a semiconductor device with high reliability and a manufacturing method of the semiconductor device that is simplified to enhance productivity, as well as reducing a thickness of the semiconductor device.